


In which the Vacuo reunion goes better than expected

by Udbsken



Category: RWBY
Genre: Gen, No thoughts head full of potential Mercury defection storylines
Language: English
Status: Completed
Published: 2021-02-26
Updated: 2021-02-26
Packaged: 2021-03-17 09:26:48
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,300
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29715075
Author URL: https://archiveofourown.org/users/Udbsken/pseuds/Udbsken
Summary: When Emerald had told the others she wanted to try to convince Mercury to join their side, they’d been skeptical. Even Emerald herself had been anticipating at least an argument, if not a fight. When they got to Vacuo, though, they were surprised to find he’d already defected.
Comments: 1
Kudos: 21





	1. Chapter 1

Yang wasn’t sure what she liked least about fighting the Hounds. The intelligence, the wings, the way Ruby looked at them like she was choking back tears every time she fired a bullet. Their guttural voices, close enough to human ones that Yang couldn’t help but imagine how they would have sounded before their throat was clogged with Grimm goo. The way they reminded her of Oscar’s injuries when they’d found him on the whale, the ones he barely seemed to notice and oh gods didn’t that just make it worse? How she had to keep her thoughts from drifting back to her mum whenever she looked at them.

 _The fact that you always get so distracted when you’re fighting them_ , she thought, jumping backwards to dodge a swipe of this one’s claws. Theoretically they should have been better at fighting the Hounds by now - they’d manage to kill a couple of them, after all. But the stupid things persisted in being difficult to deal with, and Yang had counted three aura breaks in the past few minutes. She was trying to taper her own aura out, slowly and patiently instead of all in one burst like her dad had suggested, but she could still feel it starting to run low. She wasn’t sure how long they could keep this up. 

Jaune readjusted his grip on his sword, eyes fixed on the Hound, which Weiss and Blake were currently occupied with trying to distract. “Maybe we should retreat, Ruby.” he said, looking over at her, “We’re not getting anywhere with this thing.”

“If we don’t kill it here, it’s just going to terrorise the citizens.” Ruby said doggedly, “I’m not giving up.”

Her voice was steadfast, but Yang could see how she was leaning on Crescent Rose, her leg still darkening with blood from the bite mark on her calf. Bravado or not, Yang would sooner let the Hound go free than let her little sister get hurt worse than she already was. 

“Ruby -“ she started, but cut herself off when she heard a shout from the battle.

She looked back, her heart jolting at the sight of Weiss crumpled against a cobblestone wall, the blood matting the back of her head stark against her white hair. She was breathing - Yang noted, repeating it over in her head a couple of times to calm her pulse - but the rise and fall of her chest was laboured, like she was in pain. Blake knelt next to her, her face tight with worry, the last violet sparks of her aura fluttering and fading around her. 

The Hound, meanwhile, had evidently found a target, because it was cornering Emerald, who had her back pressed against a crate and no weapon in her hands. She closed her eyes, her brow furrowing with the effort of creating an illusion Yang couldn’t see, but the Hound just huffed sightlessly and continued to lurch forwards, its jaw dangling open to reveal rows of teeth, a few of them still stained with Ruby’s blood. Yang’s semblance intensified without her meaning it to, burning through the last dregs of her aura as the memory of Salem’s fingers stroking Emerald’s cheek rose in her throat like bile. In the Brothers’ name, she wasn’t going to let that witch get her hands on Emerald. 

She raised Ember Celia, praying that she had enough ammo left, but the Hound’s jaw was already fully open and poised to close around Emerald’s head, and she could see her shaking, and _she wasn’t going to make it in time Emerald was going to die and it would be her fault_ \- and then the Hound yelped in pain and stumbled backwards before she could fire. 

Yang paused for a second, frozen in shock, before she composed herself. The Hound, backed into one of the abandoned market stalls lining the alley, was already getting its bearings back, shaking its head and rumbling words in its throat Yang couldn’t make out. She fired an explosive round into the awning before it could move, sending an avalanche of tarps and wooden support beams crashing down on its head. 

When she looked back at Emerald there was someone standing protectively in front of her - presumably they’d come from one of the roofs framing the alley. Yang’s whole body softened in the raw relief of having an ally for a second before she realised who the figure was. 

“Mercury,” she said, half sigh, half growl, at the same time as Emerald said it, considerably warmer. 

The pain-in-the-neck in question turned back to look at Emerald, ignoring Yang - probably pointedly, she thought. “Hey, Em.” he said with a grin, “Miss me?”

He tossed her one half of Thief’s Respite as he said it, which he must have retrieved from where it had skittered out of her hand earlier in the fight. 

“Maybe a little.” Emerald said, catching the weapon deftly and getting to her feet, “Not nearly as much as you missed me, I’m sure.”

The wry, joking cadence to Emerald’s voice had an element to it Yang hadn’t heard before - almost an easiness, like some tension had released Yang hadn’t even realised existed. Yang wasn’t sure how she felt about it. She was sure how she felt about Mercury being here, which was a deep desire to punch him. Not that that was precisely an emotion.

Jaune glanced expectantly over at Ren, who was frowning slightly as he stared at Mercury, as if in deep thought. After another few seconds, he shook his head, looking back at Jaune.

“Relief, tension, a bit of anxiety maybe. I can’t tell for sure.” he said, “It’s not as easy a situation as with Emerald.”

Jaune bit his lip, but Mercury spoke before he got a chance to.

“We don’t have time for this.” he said, casting a glance over his shoulder at Ruby, who straightened nervously under his gaze, “Red, do you think you can use your magic eyes on that thing?”

Ruby stammered for a second while Yang shot him a glare she hoped conveyed how little right he had to ask her sister for anything. Back at Beacon Ruby would have frozen up like a rabbit before a Grimm, but now she composed herself, holding herself like a leader even with an injured leg and no aura left. 

“Silver eyes don’t work on Hounds; it only incapacitates them for a moment,” she explained.

“But it reveals the person inside them, right? Humans are a lot easier to kill than Hounds,” Mercury said. 

Ruby parsed that over for a second, watching the Hound, who was almost free now, its red eyes flashing beneath the rubble as it tore through the last piece of debris trapping its hindquarters. 

“Fine.” she said shortly, “Buy me a minute.”

“On it,” Emerald said lightly, whirling her kama in her hand. 

If Mercury was upset about taking orders from someone younger than him he didn’t show it, just set his jaw and turned back to the Hound in time to see it burst free, snarling in its broken, human-like tongue. Yang looked away as Mercury and Emerald leapt into battle, as in sync as any Huntsman partners, to watch Ruby. 

She’d closed her eyes, her face calm as she tried to summon her silver eyes. She’d told Yang once she did it by thinking of memories, good ones, and painful ones too, the people she’d lost to time and to Salem. _Remembering who I’m protecting_ , she’d called it. Yang wondered if she was remembering their mum now. 

Ruby’s eyes snapped open - she was getting quicker at that now, Yang realised proudly. They seemed to glow from the inside, the dark silver turning to aluminium, then bright white, like liquid moonlight. The glow unfurled from her eyes like wings, blinding Yang briefly as the harsh light covered the alley. When it faded the Hound had staggered backwards, its face and shoulders revealed in a sludge of melted Grimm, fangs dotting the black goo like the person themselves was caught in the mouth of a Grimm. 

Mercury didn’t waste time - he launched upwards, landing with one foot on the Hound’s human face before flipping to the ground behind it with a burst of Dust particles. The Hound slumped to the ground a second after he landed, its mass of black muscle and bone heaving painfully for a second before collapsing sideways, sending a cloud of fine sand up in its wake. It landed so the exposed human was facing towards them, a bullet hole buried perfectly in its forehead. A clean kill.

Ruby made a small distressed noise, Yang moving closer so she could lean against her, lacing her fingers through Ruby’s and squeezing. Yang hated this, she really did. She hated seeing the woman’s face - it was definitely a woman, her long dark hair tangled with enough goo that it was hard to tell where the Grimm ended and she began - scarred and mutilated almost beyond recognition, her jaw half sealed with Grimm fluid. She hated that the woman’s soft, middle aged face made her look like she could be someone’s mum. Most of all she hated those damn silver eyes that made Ruby grip her hand so tightly and made Yang imagine Ruby’s tiny body encased in one of those hulking monsters. 

She was glad when the Grimm smoke obscured the woman, both her flesh and the black goo burning off in tandem until all that was left was a blackened skeleton lying sprawled on the cobblestones beneath them. One of her legs was missing, Yang noted sickly. Beside her, Ruby relaxed a little and looked away, Yang following her gaze to where Mercury was standing, a body between him and the rest of the group. None of them had sheathed their weapons.

“What are you doing here?” Jaune asked, saying aloud the question Yang had no doubt they were all thinking.

Mercury shrugged, his expression too difficult for Yang to read. “I defected,” he said simply, filling the alleyway with a deafening silence.

Emerald was the first to close the gap between them, because of course she was - Mercury was the reason she’d come to Vacuo in the first place. She left Salem, but she hadn’t yet managed to untangle herself from her psycho of a partner. She stepped over the ribcage like it was a bag of spilt groceries, and pulled Mercury into a fierce hug, which made Yang raise her eyebrows. She half expected him to hit her for that, but he endured it without complaint, wrapping one arm gingerly around her shoulders. His eyes were angled carefully towards the ground, lifted just enough that he could watch the rest of them without staring directly. Yang didn’t like that either. Mercury was about as subtle as she was - Emerald had always been the one good at subtlety and subterfuge in their group. If he was being cautious, that meant he thought there was some reason to be. It was very possible that the reason was because he was lying.

“What do we do now?” Ruby said, quietly enough that she was speaking just to Yang.

Her exhaustion had clearly caught up with her - she sounded tired and halfway defeated. Yang looked down at her baby sister, not sure what to say. 


	2. Chapter 2

Emerald had been restless since she’d reunited with Mercury. Very little of that restlessness was his fault - if anything he was comfortingly himself. Their conversation as the group made their way back to the inn they were renting hadn’t been the most in-depth - they were both painstakingly aware of the way the others were watching them, some still touching their weapons, as if any moment Mercury might slip and admit to her he was planning on murdering the lot of them in their sleep - but it had reminded Emerald of how much she had missed having him there to talk to. And just existing beside him really - having someone with her who she knew would have her back without question, who knew her better than - maybe anyone else? Who would call her a trusting idiot and then turn around and care about her anyway. 

Really the restlessness was because of everyone else in the group. It was pretty obvious that none of them trusted Mercury, and it was starting to get on Emerald’s nerves. There was the way everyone kept looking at her too - it was the way Penny had looked at her back at the communications tower, like _oh you poor thing, thinking that monster cares about you_. Except Penny had been right about Cinder. Mercury wasn’t anything like Cinder. Certainly he didn’t pretend to care about her the way Cinder had. Emerald dug her nails into her palm and stared at the open door in front of her. 

The inn was separated into two bedrooms - one for RWBY and one for JNOR, with Emerald and Qrow sleeping wherever they could scrounge up the space, which Emerald was used to. When they’d come in the others had had a hushed conversation that Emerald hadn’t bothered to try to enter, and then Ruby had asked Mercury to wait in the other room in a tone that implied it wasn’t much of a question. He was in there now, along with Nora and Blake acting as thinly veiled bodyguards. The others were in the same room as Emerald - Weiss now conscious and nursing a head wound, Ruby looking worried and fiddling with the bandages on her leg, and Yang pacing a hole in the carpet and occasionally glaring at the other room. Ren sat with his back against the wall, his eyes closed, presumably in mediation, and Jaune was watching him pensively. Oscar had gone quiet, but his eyes flickered about in a way that Emerald had learnt meant he was talking to Ozpin in his head. 

The silence was thickening slowly, and that wasn’t making it any easier for Emerald to stay still. What was she supposed to do, wait around until they decided Mercury was too big of a risk to be kept alive? Would they even believe her if she did try to do anything? She’d already told them she thought he was telling the truth, and that hadn’t seemed to do anything. 

Yang looked at her suddenly, her head tilted slightly. “Are you really siding with him, Emerald?”

Emerald blinked, taken aback. Before she could speak Yang continued, this time addressing the room: “Why are we even wasting our time with this? We all know Mercury’s still working for Salem. And if Emerald wants to ally with him so badly, then she’s the friend of our enemy as far as I’m concerned.”

She stepped towards Emerald, her eyes threatening even as they stayed purple. “We’re trying to stop the end of the world here - we don’t have the time or energy to play house with traitors. I’m tired of you flirting with the idea of betraying us. You and him are both murderers; why don’t you act like it and then we can fight you properly. Or better yet, I vote we just kill Emerald now and get it over with before she gets any ideas.” 

In the corner, Ruby sighed. “Agreed,” she said, looking away uncomfortably when Emerald whipped her head around to stare at her. 

Panic was starting to set in in the wake of disbelief. Was this seriously happening? Emerald had thought they trusted her. She’d thought she could read people better than this. Her hands twitched towards Thief’s Respite at her back, a thousand thoughts clouding her mind at once. Her eyes darted to the others for help, for guilt, for anything, but most of them dropped eye contact as soon as she looked at them. Ren hadn’t even opened his eyes. She was cowering, she knew she was. Like she’d cowered before Cinder. Like she’d cowered before Salem. 

“Then it’s settled.” Yang said, crossing her arms over her chest.

She opened her mouth to say something else, but the whirlpool that had been churning inside the cavity of Emerald’s chest burst forth before she could, a torrent of competing emotions spilling out of her mouth. Anger won. 

“What the hell do you know!” she yelled.

Her anger wasn’t the brittle fragility of Cinder’s temper, like a fire in a nest of dry kindling, nor was it cold and sharp like Mercury’s. Her’s was wet and desperate and thick with emotion, and her voice cracked too much to threaten, but Yang’s eyes widened anyway.

“You don’t know anything about me! You don’t know anything about Mercury! You have no idea what it’s like to have no choice in who you’ve become. You don’t know what it feels like to kill someone for the first time and cry yourself to sleep and then get up the next morning ready to do it again because you’d rather be a murderer than dead. You think we don’t know that we’ve done bad things? We’re not stupid Yang! If you killed me now -“ she choked, starting to feel tears in her throat like a lump of molten glass, “If you killed me now I’d probably deserve it for all the harm I’ve caused. But _you_ don’t get to decide what I deserve just because you’ve lived too idyllic of a life to fit us into one of your boxes. I’m not going to die because my existence is too hard for you to moralise about. And I’m not going to let you hurt my godsdamn friend!” 

Her hand was fully around the hilt of Thief’s Respite now. There were too many people here, she knew that. Even with her replenished aura, there was probably no way she could survive. But she had to try. She hadn’t come this far not to try.

Yang held up her hands. “Woah, Emerald, it’s okay. No one’s hurting either of you.” she turned to Ren as Emerald stared at her, tears still hovering on her eyelashes, “Is that enough? I’m kind of a terrible actor.”

Ren got to his feet, his eyes open. “Yeah, I got it. There were a lot of emotions, but - he was definitely scared when you threatened Emerald. And a surprised fondness when she made her speech too, so we know he’s not lying about caring about her at least.”

“Ah damn.” Yang said lightly, back to her usual self as if the last few minutes had never happened, “I owe you ten lien Rubes.”

“I’m so sorry, Emerald!” Ruby said in a rush, “We thought it would be the best way to work out if Mercury was telling the truth - that was more than we’d intended.”

Emerald blinked slowly at her, the pieces coming together in her head. It was just a test then. Ren was reading Mercury’s reactions to them threatening to kill her. She’d never been in actual danger. She sat back against the wall, letting go of Thief’s Respite and staring at the floor in disbelief. 

“Was anyone going to tell me this guy can read emotions now?” Mercury said, having appeared leaning against the doorway with his arms crossed, “Or was I just supposed to work that out on my own.”

“I can stop since it makes you uncomfortable,” Ren said coolly.

“You’re not stopping.”

“That does seem to be the case, doesn’t it,” Ren said with the flicker of a smile. 

Mercury narrowed his eyes at him like he was sizing him up, which was probably an argument Emerald was going to have to resolve later. 

“Okay then, defector.” Oscar said before Mercury could start getting into fistfights with the people who’d just decided they would trust him, “Do you wanna tell us how it happened?”


	3. Chapter 3

The first time Mercury thought about defecting was in the airship on the way to Vacuo. Well, that wasn’t strictly true. He’d thought about it before, so many times before that he couldn’t even remember which of them was his first. Maybe the first time he saw Salem, or while he was watching Emerald tend to the bruises Cinder had given her, or when everything had gone wrong at Haven, or when that kid was brought in for torturing and he’d had to fight down protective instincts he didn’t even know he possessed. Definitely when Tyrian told him Salem wanted to end the world. 

But none of those had been serious, just passing thoughts - daydreams almost, like when he thought about running away when he was a kid. At least, none of them had been as serious as he was about it now. 

Mercury wasn’t stupid. He wasn’t naive like Emerald, or delusional like Cinder. He knew how to tell when a situation was going south, and the apocalypse definitely seemed as southward as it was possible for a situation to go. Emerald clearly thought so, because he was almost positive she was planning on leaving - a concept that gave him a twisting feeling in his stomach he hadn’t yet found a name for. 

Emerald was an optimist though. Emerald didn’t have as good a sense of what she was capable of as Mercury did. Throwing herself into an unwinnable war was just about her style - he’d seen her continue to trail after Cinder like a lost puppy, after all, even while she tried to hide the occasional burn injury from him like he hadn’t done that trick a thousand times himself. Mercury didn’t play the losing side. 

Maybe there was no winning this situation though. If Salem was as undefeatable as he thought she was, then defecting was really just picking a method of death. He snuck a glance at Tyrian, who didn’t return it, to his relief. He’d tried to engage Mercury in conversation for a few hours before giving up, mostly because Mercury was silently trying not to murder him then and there and kill them both in the ensuing crash. He was dangerous though. Mercury wouldn’t have gone with him if he wasn’t dangerous. Hell, he’d probably enjoy it if Mercury defected - hunting him down in Vacuo sounded like his idea of a fun afternoon.  _ Poison - is not a good way to die,  _ Mercury concluded, biting the inside of his cheek. 

And yet, even as he tried to convince himself his best option was to stay with Salem and die quietly along with the rest of the world, his mind kept circling back to the thought of defecting, like a headache he hadn’t quite managed to shake. Slipping away from the maniac next to him would certainly be difficult, but it wasn’t impossible, and Mercury doubted Salem would bother sending reinforcements to track him down after that. Immortal witches didn’t need to worry about half rate overemotional assassins, especially when those assassins were scheduled to die in the oncoming apocalypse anyway.

What would he even do then, though? However much he’d fought against it, part of him would always be his father’s son - those wide eyed kids might as well have been in a different stratosphere from him. They may not have known a threat if it landed a whale on their city and announced the end of days was upon them, but he doubted their bleeding hearts had room enough for a murderer. Besides, joining them wasn’t something he was particularly interested in anyway. There may not have been a winning side in this stupid war, but Mercury didn’t see any reason to pick the losing side either. Plus, he’d barely even interacted with them at Beacon and they’d still been annoying enough he’d had to struggle to not maim them on the hourly.

What was left? Throwing in the towel and becoming exactly the assassin his dad had sculpted him to be? Settling down in some fantasy of a normal life so he could pretend to not know he might not even have a month left? What would a life without fighting even be worth? What would he even be worth in it?

He suppressed a sigh and leaned his head against the window, watching the ocean rush by beneath him, such a deep blue it was almost black. Gods, he was so sick of this. He’d finally broken free of his shackles only to reforge new ones around his throat, and he’d been stupid to think he wouldn’t pay the price for it. He knew why he’d leave - he’d known it for years now. It repeated itself like a patient rhythm in the base of his skull, and he’d just been pretending he couldn’t hear it.

Emerald.

Emerald, with her underdeveloped homemade fighting style that was better than it had any right to be but far too weak to survive against Salem’s forces. Emerald, who was too stubborn to admit she had nightmares even though he could see the way she sunk into him when he let her lean against him late at night. Emerald, with the fake smile she used on her marks and the real one he’d learnt the tells for after months of trying to coax it out of her for something to do on long missions. Emerald, who was stupid enough to stay with Salem because she cared about Cinder, and was stupid enough to stand against her when Cinder didn’t return the sentiment. Emerald, who was going to get herself killed. Emerald, who he had accidentally grown to care about. 

She may have died already: Salem may have already clawed her neck out with one of her Grimm hands - if that was the case then maybe he should defect anyway, just to get a chance to kick Salem’s face in before he died. But if she wasn’t, then no power in the world was worth staying away from her. 

Godsdammit. He hoped Tyrian was bad at tracking. 


End file.
